NationMaster - Encyclopedia: Prehistoric life

Prehistoric life is a term used to refer to diverse organisms that inhabited Earth from the origin of life about 3.5 billion years ago to the time when humans began to keep written records, about 3500 BC. During the course of evolution, new forms of life developed and many other forms, such as the dinosaurs, became extinct. Prehistoric life evolved over this vast timespan from simple bacteria-like cells in the oceans to algae and protozoans and complex multicellular forms such as worms, molluscs, crustaceans, fish, insects, land plants, amphibians, reptiles, birds, and mammals. On a geological timescale humans evolved very recently, about 4 million years ago at the earliest, although the exact dating is a matter of some debate. A few forms of prehistoric life like some plants and notable animals such as the coelacanth are ancient life forms and still exist today, making them living fossils. Others, like sharks, have changed little over eons. For most forms of prehistorical life that became extinct, the only record of them ever existing that remain today are fossils or rock imprints. In biology and ecology, an organism (in Greek organon = instrument) is a complex adaptive system of organs that influence each other in such a way that they function as a more or less stable whole and have properties of life. ... Earth is the third planet from the Sun. ... Pre-Cambrian stromatolites in the Siyeh Formation, Glacier National Park. ... Binomial name Homo sapiens Linnaeus, 1758 Subspecies Homo sapiens idaltuâ€ Homo sapiens sapiens Homo (genus). ... (36th century BC - 35th century BC - 34th century BC - other centuries) (5th millennium BC - 4th millennium BC - 3rd millennium BC) Events ? - Formation of the Sahara Desert 3450 (?) - Stage IId of the Naqada culture in Egypt Significant persons Inventions, discoveries, introductions ? _ Irrigation in Egypt ? - First use of Cuneiform (script) Categories... A speculative phylogenetic tree of all living things, based on rRNA gene data, showing the separation of the three domains, bacteria, archaea, and eukaryotes. ... Look up life and living in Wiktionary, the free dictionary. ... Orders & Suborders Saurischia Sauropodomorpha Theropoda Ornithischia Dinosaurs were vertebrate animals that dominated the terrestrial ecosystem for over 160 million years, first appearing approximately 230 million years ago. ... In biology and ecology, extinction is the ceasing of existence of a species or group of taxa. ... Subgroups Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular: bacterium) are a major group of living organisms. ... Cells in culture, stained for keratin (red) and DNA (green). ... The worlds oceans as seen from the South Pacific Ocean (from Okeanos, Greek for river, the ancient Greeks noticed that a strong current flowed off Gibraltar, and assumed it was a great river); covers almost three quarters (71%) of the surface of the Earth, and nearly half of the... A seaweed (Laurencia) up close: the branches are multicellular and only about 1 mm thick. ... Protozoa (in Greek protos = first and zoon = animal) are single-celled creatures with nuclei that show some characteristics usually associated with animals, most notably mobility and heterotrophy. ... Multicellular organisms are those organisms containing more than one cell, and having differentiated cells that perform specialized functions. ... A worm is an elongated soft-bodied invertebrate animal. ... Classes Caudofoveata Aplacophora Polyplacophora - Chitons Monoplacophora Bivalvia - Bivalves Scaphopoda - Tusk shells Gastropoda - Snails and Slugs Cephalopoda - Squids, Octopuses, etc. ... Classes Class Branchiopoda Subclass Phyllopoda Subclass Sarsostraca Class Remipedia Order Enantiopoda Order Nectiopoda Class Cephalocarida Order Brachypoda Class Maxillopoda Subclass Mystacocarida Subclass Copepoda Subclass Branchiura Subclass Pentastomida Subclass Tantulocarida Subclass Thecostraca Infraclass Cirripedia Class Ostracoda Order Metacopina Subclass Myodocopa Subclass Podocopa Class Malacostraca Subclass Eumalacostraca Subclass Hoplocarida Subclass Phyllocarida The... Atlantic herring, Clupea harengus: the most abundant species of fish in the world. ... Classes & Orders Subclass:Apterygota Orders Archaeognatha (Bristletails) Thysanura (Silverfish) Monura - extinct Subclass:Pterygota Infraclass: Paleoptera (paraphyletic) Orders Ephemeroptera (mayflies) Palaeodictyoptera - extinct Megasecoptera - extinct Archodonata - extinct Diaphanopterodea - extinct Protodonata - extinct Odonata (dragonflies and damselflies) Infraclass: Neoptera Superorder: Exopterygota Orders Caloneroptera - extinct Titanoptera - extinct Protorthoptera - extinct Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera... Divisions Land plants (embryophytes) Non-vascular plants (bryophytes) Marchantiophyta - liverworts Anthocerotophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) â€ Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants Adiantum pedatum (a fern... Orders Subclass Labyrinthodontia- extinct Subclass Lepospondyli- extinct Subclass Lissamphibia Anura Caudata Gymnophiona Amphibians (class Amphibia) are a taxon of animals that include all tetrapods (four-legged vertebrates) that do not have amniotic eggs. ... Orders See text. ... Orders Many - see section below. ... Orders Subclass Multituberculata (extinct) Plagiaulacida Cimolodonta Subclass Palaeoryctoides (extinct) Subclass Triconodonta (extinct) Subclass Eutheria (includes extinct ancestors)/Placentalia (excludes extinct ancestors) Afrosoricida Artiodactyla Carnivora Cetacea Chiroptera Cimolesta (extinct) Creodonta (extinct) Condylarthra (extinct) Dermoptera Desmostylia (extinct) Embrithopoda (extinct) Hyracoidea Insectivora Lagomorpha Litopterna (extinct) Macroscelidea Mesonychia (extinct) Notoungulata (extinct) Perissodactyla Pholidota Plesiadapiformes... The table and timeline of geologic periods presented here is in accordance with the dates and nomenclature proposed by the International Commission on Stratigraphy. ... Binomial name Homo sapiens Linnaeus, 1758 Subspecies Homo sapiens idaltuâ€ Homo sapiens sapiens Homo (genus). ... Divisions Land plants (embryophytes) Non-vascular plants (bryophytes) Marchantiophyta - liverworts Anthocerotophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) â€ Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants Adiantum pedatum (a fern... Phyla Porifera (sponges) Ctenophora (comb jellies) Cnidaria (coral, jellyfish, anemones) Placozoa (trichoplax) Subregnum Bilateria (bilateral symmetry) Acoelomorpha (basal) Orthonectida (parasitic to flatworms, echinoderms, etc. ... Species Latimeria chalumnae Latimeria menadoensis Coelacanth (meaning hollow thorn, from the greek coelia, ÎºÎ¿Î¹Î»Î¹Î¬ (hollow) and acanthos, Î¬ÎºÎ±Î½Î¸Î¿Ï‚ (thorn)); IPA: ) is a species of fish and represents the oldest lineage of living fish known to date. ... Look up life and living in Wiktionary, the free dictionary. ... Living fossil is a term for any living species (or clade) of organism which closely resembles species otherwise only known from fossils and has no close living relatives. ... Orders Hexanchiformes Squaliformes Pristiophoriformes Squatiniformes Heterodontiformes Orectolobiformes Carcharhiniformes Lamniformes Sharks are a group (superorder Selachimorpha) of fish, with a full cartilaginous skeleton, a streamlined body plan, with normally 5, but up to 7 (depending on species) gill slits along the side of, or beginning slightly behind, the head (in some... A fossil Ammonite Fossils (from Latin fossus, literally having been dug up) are the mineralized or otherwise preserved remains or traces (such as footprints) of animals, plants, and other organisms. ...

Category: Paleontology Orders Saurischia Sauropodomorpha Theropoda Ornithischia Dinosaurs are giant reptiles that dominated the terrestrial ecosystem for most of their 165-million year existence. ... A fossil Ammonite Fossils (from Latin fossus, literally having been dug up) are the mineralized or otherwise preserved remains or traces (such as footprints) of animals, plants, and other organisms. ... Prehistoric amphibians are various amphibians that lived before recorded history. ... Prehistoric birds are various groups of birds that lived before recorded history. ... Prehistoric fish are various groups of fishes that lived before recorded history. ... Prehistoric Insects are various groups of insects that lived before recorded history. ... Prehistoric mammals are a group of mammals that lived over 10,000 years ago. ... Prehistoric plants are various groups of plants that lived before recorded history (before about 3500 BC). ... The term Prehistoric reptile covers a broad category that is intended to help distinguish them from the dinosaurs, which were also considered reptiles, but because of their large and successful reign for many millions of years, are almost exclusively dealt with in their own category of prehistoric life. ... Orders Agnostida Redlichiida Corynexochida Lichida Phacopida Proetida Asaphida Harpetida Ptychopariida doubtful order Nektaspida Trilobites are extinct arthropods in the class Trilobita. ...